Why Hasn't My Currant Developed Well?

Are the leaves blistered and reddened?

Are the leaves yellow, stems die back?

Are the leaves spotted, yellow and drop easily?

do the leaves have rust-colored pustules on the undersides?

Are the leaves of your currants covered with the white powdery coating?

Does the fruit colors and drop early?

Aphids cause this type of damage to currants. You'll find these tiny insects clustered on leaf undersides. If the damage is not severe, ignore it; otherwise, spray with insecticidal soap, neem, or pyrethrin, making sure to get the undersides of the leaves. Dormant oil applied in the winter helps prevent aphids.

Currant borers are small caterpillars that cause currant stems to die back. As spring growth begins, you can easily spot borer-infested canes because the leaves look weak and sickly. Currant borers spend the winter in canes, pupate in the spring, and emerge as moths to reinfect currant bushes. The easiest control is to cut out and destroy infested canes as soon as you notice them.

These symptoms could indicate fungal diseases - Septoria leaf spot or Anthracnose. Since both of these diseases overwinter on old leaf litter, rake up the leaves or bury them under a thick mulch in autumn. Copper sprays also control both diseases. If defoliation occurs late in the season, it does plant little harm.

White pine blister rust is a fungal disease that is passed back and forth between white pines and various species of Ribes. European black currants are most susceptible. Red and white currants generally are not much affected. Avoid planting susceptible currants near white pines.

White, powdery patches on the leaves are caused by a fungus Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

These symptoms usually indicate Currant fruit fly larvae. The currant fruit fly lays eggs on currants and gooseberries in the spring. The larvae that hatch from these eggs feed on berries and cause them to drop. Infested berries have a dark spot surrounded by a red halo. Control this pest by destroying all infested berries as soon as you find them.

If the foliage is stripped from bushes just as leaves expand, the most likely culprit are Imported currantworms. These are the larvae of a sawfly. The larvae devour the leaves, then drop to the ground to pupate. Control their numbers with a commercial pyrethrin spray. Make sure to spray into the center of the bush.